Technical Field
This disclosure relates generally to data processing systems and, in particular to managing requests received from clients. Still more particularly, the disclosure relates to load balancing and managing requests from clients.
Background of the Related Art
Workload load balancing is a technique to distribute TCP/IP-based workload requests (connections) across similar server applications to achieve optimal resource utilization, maximize throughput, minimize response time, and to avoid overloading server applications or systems. By using multiple server applications (instead of a single server application) with load balancing, one can increase reliability through redundancy. The load balancing service usually is provided by a dedicated software program or hardware device. A workload manager provides distribution recommendations to the load balancing service (i.e. a load balancer appliance).
In workload management environments of this type, server applications that access the same data sources typically are included in the same workload. This allows monitoring agents to verify that all of these applications are available and able to handle additional connections on behalf of the workload. It also enables a workload manager to have a consolidated view of the applications in the workload, thereby enabling easy switching of the workloads between geographically separated sites (i.e., different clusters of systems). In particular, the workload manager can signal a load balancer appliance that all connections to the server applications making up the workload are to be switched at the same time to the alternate site. This ensures that access by the applications to the data sources is only done from one site at any point in time.
Many customers with mainframe applications either have combined the application and data tier on the same platform (i.e., the same operating system), while others have migrated their application tier to lower cost platforms while preserving their investment in the data tier (by leaving it on its existing platform). For example, most customers continue to maintain their business critical data on the mainframe (e.g., IBM® z/OS) systems, relying on their strength of high availability and security of their data tier. But, such customers also are writing new business applications that are hosted on a different platform, for example, web-based applications within an application server running on IBM Linux on System z. This application tier accesses the data tier residing on the mainframe. As such, such customers have two different platforms to monitor to determine the availability of a workload on a site or which site is best able to handle additional workload connections.